Ocular: Orbital And Ocular Innervation II Flashcards
Saccades
Quick, conjugate eye movements
Right frontal eye fields (FEF) initiates saccade towards the _________________ side
Contralateral side (leftwards)
Internuclear opthalmoplegia (INO)
-lesion of the MLF = INO
-adduction deficit on the side of the MLF lesion
In a right INO:
-OD cannot adduct
-OS is dissociated nystagmus when it abducts
Left 1 1/2 syndrome
Lesion of the left CN 6 nucleus, the left MLF and often the left PPRF (vice versa for right one and a half)
PPRF is in close proximity to CN6 nucleus so…
Both are typically affected by the same lesion simultaneously
Trigeminal sensory pathway
-1st order neurons synapse at the trigeminal nucleus
-2nd order neurons decussates at the medulla and then ascends to the thalamus via the ventral trigeminothalamic tract
-3rd order neurons project to somatosensory cortex
-NO SYNAPSES at the trigeminal ganglion but instead at he trigeminal spinal nucleus caudalis
Trigeminal sub-nuclei
-principal sensory nucleus
-mesencephalic nucleus
-spinal nucleus
Principal sensory nucleus is responsible for…
Tactile information to that region
Mesencephalic nucleus is responsible for…
Proprioceptive sensory information from muscles of mastication and other muscles of the head and neck
Spinal nucleus is broken up into three spinal sub nuclei for different Trigeminal facial regions:
-pars oralis
-pars interpolaris
-pars caudalis
The regions of the spinal nucleus are responsible for…
Temperature and pain
Corneal nociceptors are in…
Interpolaris/caudalis transition zone
How can the corneal pain sensation be adjusted?
Descending pain pathways
How does V1 enter the orbit?
passing through the common tendinous ring lateral to the optic nerve, THEN courses above optic nerve
Branches off the nasociliary nerve:
-ciliary ganglion
-long ciliary nerves
-posterior ethmoidal nerve
-anterior ethmoidal nerve
-intratrochlear nerve *terminal
Ciliary ganglion has NO ____________________ and branches off ___________________
sensory synapses, short ciliary nerves
Ciliary ganglion receives input from:
-cornea
-uvea
Long ciliary nerves receive input from:
-cornea
-uvea
-conjunctiva
Posterior ethmoidal nerve receives input from:
sphenoid and ethmoid sinuses
Anterior ethmoidal nerve receives input from:
-ethmoidal sinus
-nasal structures
Infratrochlear nerve is the __________ and receives input from:
Terminal branch of V1
-medial canthus/eyelids
-superior palpebral conjunctiva
-bridge of nose
Hutchinson sign
-herpes zoster (HZV) lesion on the tip of the nose
-signals that the virus is also in proximal innervated structures (cornea and uvea)
Herpes zoster virus respects the _______________ and often involves which two nerves?
Midline; infratrochlear nerve and external nasal nerve